from __future__ import annotations

__all__ = ["ring"]

import numpy as np
from numpy import cos, pi, sin

import gdsfactory as gf
from gdsfactory.component import Component
from gdsfactory.typings import LayerSpec


@gf.cell_with_module_name
def ring(
    radius: float = 10.0,
    width: float = 0.5,
    angle_resolution: float = 2.5,
    layer: LayerSpec = "WG",
    angle: float = 360,
) -> Component:
    """Returns a ring.

    Args:
        radius: ring radius.
        width: of the ring.
        angle_resolution: number of points per degree.
        layer: layer.
        angle: angular coverage of the ring
    """
    D = gf.Component()
    inner_radius = radius - width / 2
    outer_radius = radius + width / 2
    n = int(np.round(360 / angle_resolution))
    t = np.linspace(0, angle, n + 1) * pi / 180
    inner_points_x = inner_radius * cos(t)
    inner_points_y = inner_radius * sin(t)
    outer_points_x = outer_radius * cos(t)
    outer_points_y = outer_radius * sin(t)
    xpts = np.concatenate([inner_points_x, outer_points_x[::-1]])
    ypts = np.concatenate([inner_points_y, outer_points_y[::-1]])
    D.add_polygon(points=list(zip(xpts, ypts, strict=False)), layer=layer)
    return D
